Immunotherapy with Low-Dose Subcutaneous Interleukin-2 plus Beta-Interferon as a Second-Line Therapy for Metastatic Colorectal Carcinoma

Interleukin-2 for the treatment of solid tumors other than melanoma and renal cell carcinoma

Interleukin-2 (IL-2) is a lymphokine produced by T cells whose main function is to stimulate the growth and cytotoxic response of activated T lymphocytes. It has been used to stimulate the immune system for the treatment of multiples tumors. This article is intended to review the reports published from 1990 to 2004 on the IL-2 treatment of tumors other than melanoma and renal carcinoma. A literature search was made in various databases (MEDLINE, EMBASE and BioAssay), focused on IL-2 clinical efficacy in such tumors. A selection was made over 150 publications reporting on administration of IL-2 in multiple tumors: lung carcinoma (small cell and non-small cell), colorectal, gastric, pancreatic, ovarian and breast cancer, sarcomas, hepatocarcinoma, mesothelioma, and brain, urological, and head and neck tumors. IL-2 was mainly used in metastatic disease, associated with other immunotherapy or chemotherapy schedules. We conclude that adjuvant IL-2 may be of value in early stages combined with standard treatment for colon and pancreas cancers. In other neoplasms, the indication for adjuvant IL-2 has been sporadic and does not allow conclusions to be drawn. Assessment of the efficacy of IL-2 combined with chemotherapy as treatment for advanced stages is complex, due to the lack of a control, and the variety of dosages and schemes. The activity of IL-2 in monotherapy or in association with immunotherapy is clinically relevant in hepatocarcinoma, mesothelioma and in malignant overflows as palliative treatment. Randomized trials would be required in order to be able to draw conclusions about its indication in other tumors.

Immunology and immunotherapy of colorectal cancer

This review critically discusses data on immunology of colorectal cancer, starting from pathology and molecular biology, and then considering the molecular characterisation of colon cancer antigens and the clinical trials of immunotherapy. A careful evaluation of histopathological studies on intra-epithelial infiltration by T cells in primary tumours, together with the analysis of HLA expression by colorectal cancer cells, suggest that anti-tumour T cell immune responses may take place in vivo in those patients, influencing prognosis and shaping the tumour immunological profile. Moreover, the molecular characterisation of tumour antigens expressed by colorectal carcinomas, together with improved understanding of mechanisms of the immune response and more sensitive methods for the in vivo detection of T cell responses, are now allowing researchers to design new and more effective vaccination protocols, with encouraging preliminary results. By drawing together the experimental evidence from different research fields, this review provides support for the concept that colorectal carcinoma is immunogenic and may reasonably be considered as a target for immunotherapy, and attempts to address critical issues and envisage future developments in this challenging research field.

Specific immunotherapy against occult cancer metastases

We investigated the efficacy of a preparation containing High Five (H5) insect cells infected with recombinant baculovirus encoding the murine interferon-beta gene (H5BVIFN-beta) against established primary tumors and occult lung metastases. Injection of live or lyophilized H5BVIFN-beta into established subcutaneous tumors of the highly metastatic murine UV-2237m fibrosarcoma or K-1735M2 melanoma in syngeneic mice eradicated both primary tumors and preexisting lung metastases. The therapeutic effects of H5BVIFN-beta were not observed in nude mice and were diminished in syngeneic mice depleted of CD4(+) and CD8(+) T cells. Immunohistochemical staining showed that tumors injected with H5BVIFN-beta were densely infiltrated by CD4(+) and CD8(+) T cells in mice with normal CD4/CD8 complement. These data demonstrate that, unlike most immunologic approaches in which prophylaxis can be achieved but eradication of established tumor is rare, lyophilized preparations of H5BVIFN-beta can serve as a novel immunotherapy against both primary tumors and their occult metastases.

Intra-arterial infusion of 5-fluorouracil plus granulocyte-macrophage colony-stimulating factor (GM-CSF) and chemoembolization with melphalan in the treatment of disseminated colorectal liver metastases

AIMS

We compared two prospective trials of intra-arterial cytokine/chemotherapeutic infusion plus chemoembolization in the treatment of inoperable colorectal liver metastases.

MATERIALS AND METHODS

One hundred and three patients with disseminated inoperable colorectal liver metastases received intra-arterial chemotherapy with 5-FU and granulocyte-macrophage colony-stimulating factor (GM-CSF) plus chemoembolization via an angiographically positioned hepatic artery catheter. Two different regimens were used in two consecutive studies. Group A: short-term i.a. infusion of 550 mg/m(2)5-FU (days 1-4) plus 80 microg/m(2)GM-CSF (day 1+2) combined with chemoembolization with 25 mg/m(2)melphalan plus Lipiodol and Gelfoam (day 5). Group B: continuous circadian intra-arterially administered 1400 mg/m(2)5-FU infusion plus 60 mg/m(2)i.v. leucovorin and 80 microg/m(2)GM-CSF (day 1+2) combined with chemoembolization with 25 mg/m(2)melphalan plus Lipiodol and Gelfoam (day 3).

RESULTS

One hundred and three patients (62 male/41 female) with a median age of 59.9 and a median Karnofsky index of 88.5 were treated with 447 cycles of immuno-chemoembolization (group A 299, group B 148 cycles). Fifty-seven percent of these patients had received prior systemic chemotherapy. Side-effects were seen in all patients, mainly upper abdominal pain lasting 1-4 days and grade 1 or 2 vomiting. Systemic side-effects were mild and transient with a very low rate of leukopenia. Using World Health Organization response criteria, the following responses could be demonstrated: group A: CR 2.7%, PR 32.4%, MR 21.6%, SD 12.7%, NR 16.2%; group B: CR 1.0%, PR 42.4%, MR 24.2%, SD 18.2%, NR 12.1%. Time to progression was 7 as compared to 8 months. Median survival was 17 months in group A, whereas it has not been reached after 28 months (P=0.0095) in group B. There was no statistically significant difference between chemo-naive patients and patients who had received prior systemic therapy.

CONCLUSION

Immuno-chemoembolization combined with 2-day circadian administration of 5-FU is an effective tool in the treatment of disseminated colorectal liver metastases. This regimen is also effective as second-line treatment.